The term "braking resistor" is used to designate an element exhibiting electrical resistance and intended for insertion in a high tension or in a very high tension network in order to avoid the voltage surges that may arise during loss of load or of synchronization due to one or more circuit breakers opening. Such a resistor must be capable of being connected in circuit for a period of about 1 second and it must be capable of dissipating several hundred megajoules of energy.
A load resistor has been made in the United States by means of a sheet of metal wires (nickel chrome) of very great length suspended between two pylons.
This embodiment is expensive by virtue of the large area of ground required for receiving the pylons; in addition, the wires lengthen in operation and the wind can then cause them to tangle, thereby setting up undesirable short circuits.
Proposals have been made to constitute a braking resistor in the same way as a resistor for connecting neutral to ground, by means of a stack of carbon-based ceramic disks received in a metal container.
This solution is expensive and requires sulfur hexafluoride insulation in order to reduce the dimensions of the metal container.
An object of the invention is to provide a braking resistor of reduced cost price.